Ion Channels And Hyper Flashcards

1
Q

Major intracellular and extracellular ions

A

K and Na

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2
Q

Monovalent cations

A

Na and K

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3
Q

Divalent cations

A

Ca and Mg

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4
Q

Ionic gradient

A

More K inside and Na outside

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5
Q

Ion channels

A

Membrane proteins that allow contorted movement of charged ions across the cell membrane

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6
Q

Ion channel properties

A

Membrane pores
Ionotropic receptors
Gates
Ion selectivity

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7
Q

Types of gated channels and what they are activated by

A

Voltage gated - voltage
Ligand gates - ligands (intra and extraellular)
Mechanically gated - force in plasma membrane `

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8
Q

Ligand gates ion channel structure

A

Single subunit architecture :
- Transmembrane domains
- N and C terminal
- Lops link the TM domains together

Assembled architecture :
- multi subunit composition (Can have different numbers of subunits which help categorise into different categories/families )
- pentameric, tetrameric or trimeric

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9
Q

Ligand gated ion channel families

A

Cys-loop family
- nicotine acetylcholine receptor

Other
- glutamate receptors

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10
Q

Voltage gated ion channel

A

Transmebrane potential exist across plasma membrane
Inside cell is negative
Voltage gates have multiple domains
One domain is the voltage sensor - detect electrical change and rotation opens the channel pore

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11
Q

Voltage gated at -70mV, -50 to +30mv and +30mv to -50mv

A

-70mV - > closed and no Na can get through

-50 to +30mv -> open and starts to depolarise

+30mv to -50mv -> inactive. Doesn’t stay open long and conduct enough Na to depolarise the cell. Ball and chain blocks ion conduction

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12
Q

In alpha one how many TMD

A

24 organised into 4 repeating segments, each with 6 domains

1s1, 1s2, 1s3, 1s4. 1s5, 1s6
2s1, 2s2, 2s3, 2s4, 2s5, 2s6
3s1, 3s2, 3s3, 3s4, 3s5, 3s6
4s1, 4s2, 4s3, 4s4, 4s5, 4s6

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13
Q

A1 subunit

A

Is the channel pore, there will be no hole it eh middle without it

Several different A1 exist and are known as different CaV (CaV1, CaV2)

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14
Q

Auxhillary subunits

A

B, Y and a2-s

They are like friends forming a group and cannot have a channel without the all

They help the a1 subunit get to the membrane like a police escort and they regulate ion channel properties

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15
Q

Voltage gated K channels again families

A

Kv and inward rectifying channels

Different structure to NaV and CaV

Each Kv subunit has 6 TMD

4x a subunits come together as a tetramer

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16
Q

Permeability and selectivity of channels

A

Channels are permeable to ions

Non-selective channels allow more than one type of ion through

Cationic channels permeable to Na, K etc

A ionic channels permeable to Cl

17
Q

The ions that can permeate is defined by

A

The structural features of the TMD lining the channel pore

Act as a selectivity filter

18
Q

Measuring ion channels

A

Patch clamp electrophysiology

19
Q

Channel activation to in-activation

A

CaV channels sense the membrane potential

As it reaches -40mV it starts to open

Will close again while membrane is still depolarised